This invention relates to electrical generators and, particularly, relates to wind turbines and superconducting generators.
A direct drive generator driven by the blades of the wind turbine is efficient and has minimal losses due to transmission of torque from the turbine blades to the generator. Direct drive conventional generators on wind turbine towers generally have a power rating of three (3) Mega-Watts (MW) or less.
Conventional direct drive generators typically have low torque density and become too heavy for a wind turbine tower at power ratings above 3 MW. Heavy generators with power ratings above 3 MW have been used in wind turbine towers with indirect drives, which usually include a gearbox and a shaft that allows for a compact high speed generator. Gearboxes tend to be unreliable and not suitable for long life service in a wind turbine tower.
There is a long felt need for direct drive generators for wind turbines capable of generating multi Mega Watts (MW), e.g., 10 MW, of electrical power. The needed generator should be highly reliable, and have a reasonable size and weight to allow for economical shipping and installation on a wind turbine tower.